DOCSLIB.ORG

Implications for the Supercontinent Cycle

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Implications for the Supercontinent Cycle Geoscience Frontiers xxx (2017) 1e15 HOSTED BY Contents lists available at ScienceDirect China University of Geosciences (Beijing) Geoscience Frontiers journal homepage: www.elsevier.com/locate/gsf Research paper Contemporaneous assembly of Western Gondwana and final Rodinia break-up: Implications for the supercontinent cycle Sebastián Oriolo a,*, Pedro Oyhantçabal b, Klaus Wemmer a, Siegfried Siegesmund a a Geoscience Center, Georg-August-Universität Göttingen, Goldschmidtstraße 3, 37077 Göttingen, Germany b Departamento de Geología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay article info abstract Article history: Geological, geochronological and isotopic data are integrated in order to present a revised model for the Received 13 May 2016 Neoproterozoic evolution of Western Gondwana. Although the classical geodynamic scenario assumed Received in revised form for the period 800e700 Ma is related to Rodinia break-up and the consequent opening of major oceanic 6 January 2017 basins, a significantly different tectonic evolution can be inferred for most Western Gondwana cratons. Accepted 11 January 2017 These cratons occupied a marginal position in the southern hemisphere with respect to Rodinia and Available online xxx Handling Editor: R.D. Nance recorded subduction with back-arc extension, island arc development and limited formation of oceanic crust in internal oceans. This period was thus characterized by increased crustal growth in Western Keywords: Gondwana, resulting from addition of juvenile continental crust along convergent margins. In contrast, BrasilianoePan-African Orogeny crustal reworking and metacratonization were dominant during the subsequent assembly of Gondwana. Neoproterozoic The Río de la Plata, Congo-São Francisco, West African and Amazonian cratons collided at ca. 630 Collisional tectonics e600 Ma along the West Gondwana Orogen. These events overlap in time with the onset of the opening Pannotia of the Iapetus Ocean at ca. 610e600 Ma, which gave rise to the separation of Baltica, Laurentia and Metacratonization Amazonia and resulted from the final Rodinia break-up. The East African/Antarctic Orogen recorded the Introversion-extroversion subsequent amalgamation of Western and Eastern Gondwana after ca. 580 Ma, contemporaneously with the beginning of subduction in the Terra Australis Orogen along the southern Gondwana margin. However, the Kalahari Craton was lately incorporated during the Late EdiacaraneEarly Cambrian. The proposed Gondwana evolution rules out the existence of Pannotia, as the final Gondwana amalgamation postdates latest connections between Laurentia and Amazonia. Additionally, a combination of intro- version and extroversion is proposed for the assembly of Gondwana. The contemporaneous record of final Rodinia break-up and Gondwana assembly has major implications for the supercontinent cycle, as supercontinent amalgamation and break-up do not necessarily represent alternating episodic processes but overlap in time. Ó 2017, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/). 1. Introduction which was extended to South America, Australia and Antarctica by Wegener (1915). The term Gondwana was first used in the geological literature to The amalgamation of Gondwana started at ca. 630 Ma and refer to a plant-bearing series in India and was afterwards extended to ca. 550e530 Ma, when subduction along its proto- extended to the Gondwana system (Feistmantel, 1876; Medlicott Pacific margin was already established (Dalziel, 1997; Cordani and Blanford, 1879, and references therein). Based on similarities et al., 2003; Meert and Torsvik, 2003; Cawood, 2005; Collins and in the PaleozoiceMesozoic geological and fossiliferous record of Pisarevsky, 2005; Cawood and Buchan, 2007). Likewise, Pannotia India and other continental masses, Suess (1885) proposed the was considered as a Late Neoproterozoic “short-lived” supercon- existence of a supercontinent and coined the name Gondwanaland, tinent that included Laurentia and Gondwanan domains, prior to Gondwana final configuration (Powell and Young, 1995; Dalziel, 1997). On the other hand, the break-up of Rodinia took place in e * Corresponding author. two phases at ca. 800 700 Ma and after ca. 600 Ma, being the later E-mail addresses: [email protected], [email protected] (S. Oriolo). coeval with the timing of Gondwana assembly (Cordani et al., 2003; Peer-review under responsibility of China University of Geosciences (Beijing). Cawood, 2005; Li et al., 2008). Late Neoproterozoic paleogeography http://dx.doi.org/10.1016/j.gsf.2017.01.009 1674-9871/Ó 2017, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC- ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: Oriolo, S., et al., Contemporaneous assembly of Western Gondwana and final Rodinia break-up: Implications for the supercontinent cycle, Geoscience Frontiers (2017), http://dx.doi.org/10.1016/j.gsf.2017.01.009 2 S. Oriolo et al. / Geoscience Frontiers xxx (2017) 1e15 thus resulted from major geodynamic processes that might be a whereas the Congo Craton in Africa exhibits several distinct Meso- priori linked to the evolution of Rodinia, Pannotia and/or Gond- proterozoicmagmaticeventsatca.1.50,1.38and1.10Ga(Ernst et al., wana (Fig. 1). 2013). Despite being almost coeval with the timing of Rodinia as- Two end-member processes were proposed for the formation of sembly, the youngest event comprises gabbroenorite dykes that supercontinents, namely introversion and extroversion, depending resulted from intraplate magmatism (Ernst et al., 2013). on whether internal or external oceans of a supercontinent are A different situation can be observed in the Kalahari Craton, closed to form the next one, respectively (Fig. 2; Nance et al., 1988; which presents an ArcheanePaleoproterozoic nucleus surrounded Hartnady, 1991; Hoffman, 1991; Murphy and Nance, 2003, 2005, by Late Mesoproterozoic mobile belts. The northern (present co- 2013; Mitchell et al., 2012; Evans et al., 2016). Internal oceans ordinates) SinclaireGhanzieChobe Belt recorded arc-related mag- comprise juvenile crust that forms after break-up of the previous matism resulting in collision and subsequent post-collisional supercontinent and external ocean crust predates the previous magmatism at ca. 1.1 Ga (Kampunzu et al.,1998; Becker et al., 2006). supercontinent (Murphy and Nance, 2003, 2005). In terms of To the southwest, collision-related deformation and meta- paleogeography, introversion implies that the location of a super- morphism in the Namaqua Belt has been placed at ca. 1.20e1.18 Ga continent is the same of its predecessor, whereas the successor is (e.g., Miller, 2008; Colliston et al., 2015; Cornell et al., 2015), located in the opposite hemisphere in the case of extroversion although extension in a back-arc setting was alternatively consid- (Mitchell et al., 2012). In the particular case of Gondwana, an ered for this major tectonothermal event (Bial et al., 2015a, b). The extroversion model has been typically considered (Hoffman, 1991; southeastern margin of the Kalahari Craton, in turn, is bounded by Murphy and Nance, 2003, 2005, 2013; Evans et al., 2016). the Natal Belt, which recorded accretion of island arc complexes Based on a review of geological, geochronological and isotopic (e.g., Thomas, 1989; Jacobs and Thomas, 1994; Spencer et al., 2015). evidences, a revised model for the Neoproterozoic evolution of On the other hand, the Umkondo LIP intruded the Kalahari Craton Western Gondwana is presented in this work. Relationships with at ca. 1.1 Ga (Hanson et al., 2004) and was correlated with coeval Rodinia break-up and the evolution of the Terra Australis Orogen intraplate extensional magmatism in the Congo Craton (Ernst et al., are discussed, and implications for the supercontinent cycle are 2013). In contrast, Becker et al. (2006) interpreted this intrusion as analyzed as well. the result of post-collisional processes. Although it seems to be clear that the Río de la Plata, West African 2. Pre-Gondwana configuration and Congo-São Francisco cratons were not part of Rodinia (Fig. 1a), the position of the Kalahari Craton is still uncertain. However, even if Many contributions attempted to elucidate Late Mesoproter- being part of Rodinia, the Kalahari Craton might already rift away at ozoiceEarly Neoproterozoic paleogeography (e.g., Powell et al., ca. 700 Ma (Jacobs et al., 2008). Rifting at ca. 800e700 Ma gave rise 1993; Dalziel et al., 2000; Kröner and Cordani, 2003; Pisarevsky to the opening of a major oceanic basin between Laurentia and et al., 2003; Tohver et al., 2006; Li et al., 2008; Evans, 2009), eastern Gondwanan cratons and was succeeded by a second rifting which represents a key point to understand the history of Gond- event starting after ca. 610e600 Ma (Fig. 1a) that triggered the wana amalgamation. The assembly of Rodinia took place at ca. opening of the Iapetus Ocean between Laurentia, Baltica and Ama- 1.1e1.0 Ga and, although most authors agree on the fact that the zonia (e.g., Cawood et al., 2001; Meert and Torsvik, 2003; Li et al., Amazonian Craton was part of Rodinia (Dalziel et al., 2000; Tohver 2008). In any case, most reconstructions do not consider Meso- et al., 2006; Li et al., 2008;
Load more

Recommended publications
  • Two Contrasting Phanerozoic Orogenic Systems Revealed by Hafnium Isotope Data William J
    ARTICLES PUBLISHED ONLINE: 17 APRIL 2011 | DOI: 10.1038/NGEO1127 Two contrasting Phanerozoic orogenic systems revealed by hafnium isotope data William J. Collins1*(, Elena A. Belousova2, Anthony I. S. Kemp1 and J. Brendan Murphy3 Two fundamentally different orogenic systems have existed on Earth throughout the Phanerozoic. Circum-Pacific accretionary orogens are the external orogenic system formed around the Pacific rim, where oceanic lithosphere semicontinuously subducts beneath continental lithosphere. In contrast, the internal orogenic system is found in Europe and Asia as the collage of collisional mountain belts, formed during the collision between continental crustal fragments. External orogenic systems form at the boundary of large underlying mantle convection cells, whereas internal orogens form within one supercell. Here we present a compilation of hafnium isotope data from zircon minerals collected from orogens worldwide. We find that the range of hafnium isotope signatures for the external orogenic system narrows and trends towards more radiogenic compositions since 550 Myr ago. By contrast, the range of signatures from the internal orogenic system broadens since 550 Myr ago. We suggest that for the external system, the lower crust and lithospheric mantle beneath the overriding continent is removed during subduction and replaced by newly formed crust, which generates the radiogenic hafnium signature when remelted. For the internal orogenic system, the lower crust and lithospheric mantle is instead eventually replaced by more continental lithosphere from a collided continental fragment. Our suggested model provides a simple basis for unravelling the global geodynamic evolution of the ancient Earth. resent-day orogens of contrasting character can be reduced to which probably began by the Early Ordovician12, and the Early two types on Earth, dominantly accretionary or dominantly Paleozoic accretionary orogens in the easternmost Altaids of Pcollisional, because only the latter are associated with Wilson Asia13.
    [Show full text]
  • (Ordovícico) En El Segmento Andino Central Del Orógeno Terra Australis
    XII Congreso Geológico Chileno Santiago, 22-26 Noviembre, 2009 S9_011 La tectónica acrecional oclóyica (Ordovícico) en el segmento andino central del orógeno Terra Australis Astini R.A.1, Martina F.1 1Laboratorio de Análisis de Cuencas, CICTERRA-Universidad Nacional de Córdoba, Av. Velez Sarsfield 1611, 2º piso, of. 7, X5016GCA Córdoba, Argentina. [email protected] En el marco del orógeno acrecional de Terra Australis [1] se reconocen intervalos temporales con acreción de terrenos e interrupción momentánea de la subducción que afectan diferencialmente al margen protoandino y permiten reconocer segmentos con características e historias contrastadas en los Andes. Sobre la base de una revisión conceptual y bibliográfica y de nuevos estudios estratigráficos, geoquímicos e isotópicos en la región del antepaís andino central se propone un mecanismo acrecional alternativo para la etapa de orogénesis ordovícica, que es la de mayor extensión que haya afectado al margen proto-pacífico antes de la orogenia gondwánica, con que finaliza la historia acrecional paleozoica. Dentro de la etapa de orogénesis oclóyica se propone separar la colisión del terreno de Precordillera [2] en el segmento andino central entre 27°30’ y 36°30’ LS aproximadamente (~1000 km de longitud), de la acreción de un bloque alargado (sliver o ribbon terrane) de basamento mesoproterozoico de mucho mayor extensión longitudinal (superior los 2000 km) (Fig. 1) que, de alguna manera, ha sido denominado Occidentalia [3]. Este último incluiría en los Andes Centrales a los terrenos de basamento mesoproterozoico correspondientes a las Sierras Pampeanas Occidentales, ubicados al oeste del cinturón de Famatina y su continuación septentrional en la Puna Catamarqueña (afloramientos de Casadero Grande) y en los terrenos de Arequipa-Antofalla.
    [Show full text]
  • Billion Year Cyclicity Through Earth History: Causes and Consequences
    Geophysical Research Abstracts Vol. 21, EGU2019-12040, 2019 EGU General Assembly 2019 © Author(s) 2019. CC Attribution 4.0 license. Billion year cyclicity through Earth history: causes and consequences William Collins (1), Erin Martin (1), Ross Mitchell (1), Brendan Murphy (2), and Chris Spencer (1) (1) Curtin University, School of Earth & Planetary Sciences, Perth, Australia ([email protected]), (2) St. Francis Xavier University, Department of Earth Sciences, Antigonish, NS, B2G 2W5, Canada A billion year-scale (gigacycle) periodicity in global radiogenic Hf and Sr isotopic trends is investigated by integrating data from tectonics, geodynamics, and palaeomagnetism, in order to build a holistic geodynamic model linking modes of mantle convection to plate tectonic motions over the last 2,500 Myr. The gigacycle reflects an alternating dominance between degree-2 and degree-1 mantle convective flow, manifest as the presence or absence of a hemispheric subduction girdle, respectively. Degree-1 convection involves a single upwelling and opposed downwelling zone, whereas degree-2 has two upwelling zones located antipodally. Present-day convection is degree-2, with the two modern upwelling zones as the Pacific and African superplumes, located on either side of the circum-Pacific subduction girdle. The girdle is geologically recorded by circum-Pacific accretionary orogens, and has existed since ∼550 Myr, indicating that degree-2 convection characterises the Phanerozoic eon. Degree-1 convection resulted in the amalgamation of Columbia ca. 2,000 Myr ago and Gondwana ca. 550 Myr ago accompanied by peaks in crustal reworking (-"Hf), whereas degree-2 convection produced Nuna ca. 1,600 Myr ago and Pangaea 200 Myr ago accompanied by peaks in mantle input (+"Hf).
    [Show full text]
  • Early Evolution of the Proto-Andean Margin of South America
    Early evolution of the Proto-Andean margin of South America C. W. Rapela Centro de Investigaciones Geológicas, Universidad Nacional de La Plata, Calle 1 No. 644, 1900 La Plata, Argentina R. J. Pankhurst British Antarctic Survey, Cambridge CB30ET, United Kingdom C. Casquet Departamento de Petrología y Geoquímica, Universidad Complutense, 28040 Madrid, Spain E. Baldo J. Saavedra CSIC, Instituto de Agrobiología y Recursos Naturales, 37071 Salamanca, Spain C. Galindo Departamento de Petrología y Geoquímica, Universidad Complutense, 28040 Madrid, Spain ABSTRACT INTRODUCTION From a detailed study of a 500 km transect in the Sierras Pampeanas, central-west Argen- The evolution of the Gondwana margin pro- tina, two pre-Silurian tectono-magmatic episodes are recognized and defined, each culminating posed here is based on new geochemical, isotopic, in micro-continental collisions against the proto-Andean margin of Gondwana. The Pampean petrological, and sedimentological data from a orogeny started in Early Cambrian time with short-lived subduction, indicated by ca. 535 Ma 500 km traverse across the Eastern Sierras Pam- calc-alkaline granitoids. Following Pampean terrane collision, burial to granulite facies condi- peanas and Precordillera (Fig. 1). Pre-Silurian tions (ca. 9 kbar) generated widespread migmatites and ca. 520 Ma highly peraluminous gran- metamorphic and magmatic history is inferred ites in the Eastern Sierras Pampeanas. After brief quiescence, a second major episode, the from (1) dating by conventional U-Pb on abraded Famatinian orogeny, started with subduction ca. 490 Ma, forming a wide continental arc and zircons, U-Pb SHRIMP analyses, and whole-rock ensialic backarc basin. This heralded the approach of Laurentia to Gondwana, during which Rb-Sr and K-Ar, (2) thermo-barometry based on the Precordillera terrane separated from the southern Appalachian region, finally colliding with microprobe mineral analyses, and (3) Nd and Sr Gondwana in Silurian–Devonian time.
    [Show full text]
  • Upper Mantle P and S Wave Velocity Structure of the Kalahari Craton And
    RESEARCH LETTER Upper Mantle P and S Wave Velocity Structure of the 10.1029/2019GL084053 Kalahari Craton and Surrounding Proterozoic Key Points: • Thick cratonic lithosphere extends Terranes, Southern Africa beneath the Rehoboth Province and Kameron Ortiz1, Andrew Nyblade1,5 , Mark van der Meijde2, Hanneke Paulssen3 , parts of the northern Okwa Terrane 4 4 5 2,6 and Magondi Belt Motsamai Kwadiba , Onkgopotse Ntibinyane , Raymond Durrheim , Islam Fadel , • The northern edge of the greater and Kyle Homman1 Kalahari Craton lithosphere lies along the northern boundary of the 1Department of Geosciences, Pennsylvania State University, University Park, PA, USA, 2Faculty for Geo‐information Rehoboth Province and Magondi Science and Earth Observation (ITC), University of Twente, Enschede, Netherlands, 3Department of Earth Sciences, Belt 4 • Cratonic mantle lithosphere Faculty of Geosciences, Utrecht University, Utrecht, Netherlands, Botswana Geoscience Institute, Lobatse, Botswana, 5 6 beneath the Okwa Terrane and School of Geosciences, The University of the Witwatersrand, Johannesburg, South Africa, Geology Department, Faculty Magondi Belt may have been of Science, Helwan University, Ain Helwan, Egypt chemically altered by Proterozoic magmatic events Abstract New broadband seismic data from Botswana and South Africa have been combined with Supporting Information: existing data from the region to develop improved P and S wave velocity models for investigating the • Supporting Information S1 upper mantle structure of southern Africa. Higher craton‐like velocities are imaged beneath the Rehoboth Province and parts of the northern Okwa Terrane and the Magondi Belt, indicating that the Correspondence to: northern edge of the greater Kalahari Craton lithosphere lies along the northern boundary of these A. Nyblade, terranes.
    [Show full text]
  • Locating South China in Rodinia and Gondwana: a Fragment of Greater India Lithosphere?
    Locating South China in Rodinia and Gondwana: A fragment of greater India lithosphere? Peter A. Cawood1, 2, Yuejun Wang3, Yajun Xu4, and Guochun Zhao5 1Department of Earth Sciences, University of St Andrews, North Street, St Andrews KY16 9AL, UK 2Centre for Exploration Targeting, School of Earth and Environment, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia 3State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China 4State Key Laboratory of Biogeology and Environmental Geology, Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China 5Department of Earth Sciences, University of Hong Kong, Pokfulam Road, Hong Kong, China ABSTRACT metamorphosed Neoproterozoic strata and From the formation of Rodinia at the end of the Mesoproterozoic to the commencement unmetamorphosed Sinian cover (Fig. 1; Zhao of Pangea breakup at the end of the Paleozoic, the South China craton fi rst formed and then and Cawood, 2012). The Cathaysia block is com- occupied a position adjacent to Western Australia and northern India. Early Neoproterozoic posed predominantly of Neoproterozoic meta- suprasubduction zone magmatic arc-backarc assemblages in the craton range in age from ca. morphic rocks, with minor Paleoproterozoic and 1000 Ma to 820 Ma and display a sequential northwest decrease in age. These relations sug- Mesoproterozoic lithologies. Archean basement gest formation and closure of arc systems through southeast-directed subduction, resulting is poorly exposed and largely inferred from the in progressive northwestward accretion onto the periphery of an already assembled Rodinia. presence of minor inherited and/or xenocrys- Siliciclastic units within an early Paleozoic succession that transgresses across the craton were tic zircons in younger rocks (Fig.
    [Show full text]
  • A History of Proterozoic Terranes in Southern South America: from Rodinia to Gondwana
    + MODEL GEOSCIENCE FRONTIERS -(-) (2011) 1e9 available at www.sciencedirect.com China University of Geosciences (Beijing) GEOSCIENCE FRONTIERS journal homepage: www.elsevier.com/locate/gsf REVIEW A history of Proterozoic terranes in southern South America: From Rodinia to Gondwana C. Casquet a,*, C.W. Rapela b, R.J. Pankhurst c, E.G. Baldo d, C. Galindo a, C.M. Fanning e, J.A. Dahlquist d, J. Saavedra f a Departamento de Petrologıa y Geoquımica, IGEO (Universidad Complutense, CSIC), 28040 Madrid, Spain b Centro de Investigaciones Geologicas (CONICET-UNLP), 1900 La Plata, Argentina c Visiting Research Associate, British Geological Survey, Keyworth, Nottingham NG12 5GG, United Kingdom d CICTERRA (CONICET-UNC), 5000 Cordoba, Argentina e Research School of Earth Sciences, The Australian National University, Canberra, Australia f Instituto de Agrobiologıa y Recursos Naturales CSIC, 37071 Salamanca, Spain Received 3 August 2011; accepted 8 November 2011 KEYWORDS Abstract The role played by Paleoproterozoic cratons in southern South America from the Mesopro- Paleoproterozoic; terozoic to the Early Cambrian is reconsidered here. This period involved protracted continental amal- Cratons; gamation that led to formation of the supercontinent Rodinia, followed by Neoproterozoic continental Grenvillian; break-up, with the consequent opening of Clymene and Iapetus oceans, and finally continental Neoproterozoic rifting; re-assembly as Gondwana through complex oblique collisions in the Late Neoproterozoic to Early SW Gondwana assembly Cambrian. The evidence for this is based mainly on a combination of precise U-Pb SHRMP dating and radiogenic isotope data for igneous and metamorphic rocks from a large area extending from the Rio de la Plata craton in the east to the Argentine Precordillera in the west and as far north as Arequipa in Peru.
    [Show full text]
  • Early Palaeozoic Continental Growth in the Tasmanides of Northeast Gondwana and Its Implications for Rodinia Assembly and Rifting Chris L
    University of Wollongong Research Online Faculty of Science, Medicine and Health - Papers Faculty of Science, Medicine and Health 2015 Early Palaeozoic continental growth in the Tasmanides of northeast Gondwana and its implications for Rodinia assembly and rifting Chris L. Fergusson University of Wollongong, [email protected] R A. Henderson James Cook University Publication Details Fergusson, C. L. & Henderson, R. A. (2015). Early Palaeozoic continental growth in the Tasmanides of northeast Gondwana and its implications for Rodinia assembly and rifting. Gondwana Research, 28 (3), 933-953. Research Online is the open access institutional repository for the University of Wollongong. For further information contact the UOW Library: [email protected] Early Palaeozoic continental growth in the Tasmanides of northeast Gondwana and its implications for Rodinia assembly and rifting Abstract Gondwana formed in the Neoproterozoic to Cambrian mainly from collision along the East African and Kuunga orogens at about the same time that the Gondwana palaeo-Pacific facing margin became a long-lived active margin and formed the Terra Australis Orogen. This orogen, and in particular the Tasman Orogenic Belt (the Tasmanides) sector of eastern Australia, is distinguished by widespread shortening of quartz turbidite successions and underlying oceanic basement, with less abundant island arc assemblages. Early Palaeozoic accretionary development of the Tasmanides followed Rodinia breakup at 800-750 Ma to form the palaeo-Pacific cO ean. In eastern Australia, a second rifting episode at 600-580 Ma is more widely developed with siliciclastic sedimentation and rift-related igneous activity. In parts of the Delamerian Orogen of South Australia and northwestern New South Wales and in the exposed northern Thomson Orogen of north and central Queensland, the rift-related sedimentary successions have a dominant 1.3 to 1 Ga detrital zircon age signature implying local sources.
    [Show full text]
  • The Proto-Andean Margin of Gondwana: an Introduction
    Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021 The proto-Andean margin of Gondwana: an introduction R. J. PANKHURST 1 & C. W. RAPELA 2 1 British Antarctic Survey, c/o NERC Isotope Geosciences Laboratory, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG, UK 2 Centro de Investigaciones Geol6gicas, Universidad Naeional de la Plata, 644 Calle No. 1, 1900 La Plata, Argentina Abstract: A basic background is presented for the discussion of the Early Palaeozoic geology of western Argentina covered by this book. This includes the definition and terminology of orogenic cycles on this part of the Gondwana margin, represented by the Eastern Sierras Pampeanas. The Pampean orogeny (Early Cambrian) relates to an intense but short-lived period of terrane collision predating the rifting of the Precordillera terrane from Laurentia. The Famatinian cycle is predominantly represented by intense subduction- related magmatism of Early-Middle Ordovician age, developed on the continental margin of Gondwana during the rifting and drifting of the Precordillera terrane. The Grenvillian basement of the latter is further exemplified by a new Rb-Sr whole-rock isochron age of 1021 + 12Ma for orthogneisses from the Western Sierras Pampeanas. A mid-Ordovician granite in this area (dated at 481 4-6 Ma by U-Pb ion microprobe data) may be related to rifting while the Precordillera terrane was still attached to Laurentia. A divergence of opinion is pointed out between some authors in this book who favour mid-Ordovician collision of the Precordillera with Gondwana, and others who place it much latter, in Silurian or Devonian times.
    [Show full text]
  • An Approach to the Brasiliano-Pan African Cycle and Orogenic Collage
    155 by Benjamim Bley de Brito Neves1, Mário da Costa Campos Neto1, and Reinhardt Adolfo Fuck2 From Rodinia to Western Gondwana: An approach to the Brasiliano-Pan African Cycle and orogenic collage 1- Instituto de Geociências - Universidade de São Paulo. S. Paulo-SP. 2- Instítuto de Geociências - Universidade de Brasílía. Brasílía-DF. The basement of the South American platform displays east), Tocantins (Central-eastern, part of the Central- the lithostructural and tectonic records of three major western), Pampean (Central-southwestern) and Man- orogenic collages: Middle Paleoproterozoic (or tiqueira (East-southeast). Transamazonian), Late Mesoproterozoic/Early Neopro- terozoic and Late Neoproterozoic/Cambrian, the Brasil- Introduction iano-Pan African collage. The first two collages have their records in the basement of the Syn-Brasiliano cra- The history of the geologic evolution of the South American conti- tons and Brasiliano Fold Belts. nent from the Neoproterozoic to the early Cambrian is recording all The development of the Brasiliano-Pan African the steps of the development of a complete and wide tectonic cycle, collage started in Early Neoproterozoic times, with the in terms of J.T. Wilson. This means, from the fission/disarticulation of a former Late Mesoproterozoic Supercontinent (Rodinia) – up to first events of breakup of the Rodinia Supercontinent, the further fusion/agglutination of a newer supercontinent — West- and it has been characterized by diachrony since their ern Gondwana (Pannotia). early beginnings. The processes of break up and fission For the two major tectonic phenomena then developed (fission and subsequent fusion) it is necessary to remark, since now, the took place in different time intervals (ca.
    [Show full text]
  • Geologia Argentina
    INSTITUTO DE GEOLOGÍA Y RECURSOS MINERALES GEOLOGÍARASGOS ESTRUCTURALES ARGENTINA DEL TERRITORIO ARGENTINO CAPÍTULO 71524 ANALES 29 (24): 715-784, BUENOS AIRES, 1999 RASGOS ESTRUCTURALES DEL TERRITORIO ARGENTINO 1. EVOLUCION TECTÓNICA DE LA ARGENTINA Victor A. Ramos INTRODUCCIÓN ñas. Aceptó los movimientos paleozoicos y mesozoicos pro- puestos por Keidel (1921), pero brindó un cuadro más com- El objetivo del presente capítulo es brindar una síntesis pleto para el levantamiento de los Andes, reconociendo para de la evolución geológica de Argentina, con especial énfasis diferentes segmentos y regiones movimientos y fases de en su desarrollo tectónico. distinta intensidad, generando una adecuada nomenclatura Se analizarán los diferentes ciclos orogénicos y los para la época. procesos que llevaron a la constitución actual de la cordillera Durante el apogeo de la teoría geosinclinal correspondió andina y su basamento extraandino. Se prestará especial a Borrello (1963, 1968, 1969) la elaboración de un esquema atención a los diferentes eventos magmáticos, a la deforma- de evolución tectónica, que dentro de ese marco, reconocía ción y al metamorfismo concomitante y a las características los ciclos protoídico, paleoídico y neoídico para la formación paleogeográficas que controlaron la historia geológica del de los diferentes sistemas montañosos. Reconoció las dife- territorio nacional. rentes fases orogénicas, correlacionándolas con sus pares de El concepto de ciclo orogénico se utiliza para enmarcar otras regiones del mundo, asumiendo una sincroneidad y los eventos que a partir de procesos extensionales, formación correlación directa con ellas. y destrucción de corteza oceánica y deformación poserior, Stipanicic y Rodrigo (1970 a y b), más tarde Turner y llevan a la formación de cadenas montañosas (Dewey y Bird, Méndez (1975), Aceñolaza y Toselli (1976) y Salfity et al.
    [Show full text]
  • Pannotia to Pangaea: Neoproterozoic and Paleozoic Orogenic Cycles in the Circum-Atlantic Region: a Celebration of the Career of Damian Nance
    Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021 Pannotia to Pangaea: Neoproterozoic and Paleozoic Orogenic Cycles in the Circum-Atlantic Region: A celebration of the career of Damian Nance J. Brendan Murphy1,2*, Robin A. Strachan3 and Cecilio Quesada4 1Department of Earth Sciences, St Francis Xavier University, Antigonish, Nova Scotia, B2G 2W5, Canada 2Earth Dynamics Research Group, the Institute for Geoscience Research (TIGeR), School of Earth and Planetary Sciences, Curtin University, WA 6845, Australia 3School of the Environment, Geography and Geosciences, University of Portsmouth, Portsmouth PO1 3QL, UK 4Instituto Geológico y Minero de España (IGME), C/Ríos Rosas, 23, 28003 Madrid, Spain JBM, 0000-0003-2269-1976 *Correspondence: [email protected] Special Publication 503 celebrates the career of between tectonic events and biogeochemical cycles, R. Damian Nance. It features 27 articles, with more as exemplified in the late Neoproterozoic–Early than 110 authors based in 18 different countries. Cambrian by the amalgamation of Gondwana span- The wide range of topics presented in this volume ning a time interval characterized by dramatic climate mirrors the breadth and depth of Damian’s contribu- swings, profound changes in the chemistry of the tions, interests and expertise. Like Damian’s papers, oceans and atmosphere, and the evolution of multi- the contributions range from the predominantly con- cellular animals (see Hoffman 1991; Hoffman et al. ceptual to detailed field work, but all are targeted at 1998; Narbonne 2010; Knoll 2013). understanding important tectonic processes. Their As reconstructions became more refined, scope not only varies in scale from global to regional several authors proposed that Gondwana was part to local, but also in the range of approaches required of a larger entity called Pannotia that included Lau- to gain that understanding.
    [Show full text]